Telephone-exchange system.



W. A. FRIOKE.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED APB.11, 1908.

. 987,128.v Patented Mar.21,1911.

WITNESSES:

MLLIAM A. FRIcKE IN VENTOR 7m: lvoxms PETERS cm. wAsnmcrou, n. c.

UNITED STATES PATENT OFFICE WILLIAM A. FRICKE, OF CHICAGO, ILLINOIS,ASSIGNOR TO MONARCI-I TELEPHONE MANUFACTURING COMPANY, OF CHICAGO,ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Application filed April 11, 1908.

Patented Mar. 21, 1911. Serial No. 426,574.

To (ZZZ whom it may concern:

Be it known that I, VVILLIAM A. Fni'ojnn, citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Telephone- ExchangeSystems, of which the following is a full, clear, concise, and exactdescription, reference being had to the accom 'ianying drawings, forminga part of this specification.

My invention relates to that class of telephone exchange systems inwhich manually operated generators are employed at the subscribersstations for the purpose of effecting signals. at the exchange. As iswell known, hand-operated magneto generators are most usually employedfor this purpose at the subscribers stations, though I do not wish to belimited in an embodiments of my invention to the use of magneto generators. In other words, therefore, my iiivention relates to that classof telephone exchange systems in which manually operated generators areemployed at subscribers stations for the purpose of impressing wave formcurrent upon the subscribers lines for the purpose of intermittentlyoperating signal devices at the exchange.

The primary object of my invention is to provide signaling mechanism atthe exchange whose operation is controlled by wave form currentimpressed upon the telephone lines at subscribers stations and whichsignaling apparatus is adapted either to present to the operator a callor discon nect signal, according to the prime function of the signaldevice, or to indicate that a subscriber desires the attention of theoperator. In common battery practice the call and supervisory signalinglamps through the relay mechanism associated therewith, are each adaptedto the double purpose of indicating to the operator that subscribers arethrough conversation or desire a connection, according to the primefunction of the lamp, or that a subscriber desires the attention of anoperator after having effected the initial presentation of a signal. aIn magneto switchboard telephony, however, as hitherto practiced, theclearing-out signal devices were in the form of electro-magnets havingshutters, which, when released, served to indicate to the operator thatthe conversation between connected lines was finished, this signalingdevice being incapable of conveying to the operator that her attentionwas desired by a subscriber.

Generally speaking, my invention resides in equipping a clearing-outsignaling device or a line signaling device in a magneto switch-boardwith apparatus whereby such signaling device may not only fulfil itsprime function, but may also serve to indicate to the operator that herattention is clesired by a subscriber who happens to be operating themanually actuated current generator at his station.

I will explain my invention more fully by reference to the accompanyingdrawing, showing the preferred embodiment thereof, in which- Figure 1diagrammatically indicates so much of a magneto switch-board telephoneexchange system as is necessary to an understanding of my invention, thecord circuit illustrated in this figure including single supervisoryapparatus. Fig. 2 illustrates a system similar to Fig. 1, with theexception that the cord circuit illustrated in Fig. 2 in cludes doublesupervisory signal apparatus.

Like parts are indicated by similar char acters of reference throughoutboth figures.

I have indicated at each of the sub-stations a b in the systemsillustrated in Figs. 1 and-2, one of many types of apparatus whichinclude one of many types of manually operated current generatingdevices adapted to impress wave form current upon the subscriberstelephone lines, and it will, therefore, be unnecessary for me todescribe in detail the apparatus shown at these substations, it beingsufficient tounderstand that a manually operated generator, such as thegenerator 0, is adapted to impress wave form current of suitablecharacter, preferably alternating current, 'upon the correspondingtelephone line whose limbs termi nate in springs cl and e of line jacks.diagrammatically illustrated a cord circuit for each of the two systemsshown, each cord circuit including an answering plug f and a,

connecting plug provided with tip and sleeve contacts, 5 ownrespectively n en gagement with the associate jack springs d and e. Ihave indicated the terminals h of an operators telephone set and theterminals 2' of a ringing generator whose association I have.

with the cord circuit apparatus is well understood by those skilled inthe art, on which account it is unnecessary to make further mentionthereof.

Referring now more particularly to the system shown in Fig. 1, I haveillustrated an electro-magnet having a core common to two windings Z andm, one terminal of each of these windings being shown in connection withthe sleeve strand of the cord. circuit and with each other, while theother terminals of these windings, although in conductive relation withthe tip strand of the cord circuit, are separated directly from eachother by means of a condenser 12, of small capacity for reasons wellknown. This condenser n is preferably of small capacity, in consequenceof which it will be more transparent to voice currents (which are ofvery high frequency) than to signaling currents (which are of very lowfrequency as compared with voice currents). The condenser n, forpurposes of signaling, thus serves to limit the association of the coilZto the answering end of the cord circuit and the association of thecoil m to the connecting end of the cord circuit, whereby the coil Z isalone within the control of the generator c of the calling subscriberand the coil m is alone within the control of the generator c of thecalled subscriber. The condenser n, of course, serves to complete thetelephonic continuity of the tip strand, so that the voice currents donot have to thread the coils Z and on. While I thus provide theelectro-magnet 7a with the independently controlledcoils Z and m, I donot wish to be limited to a system in which the disconnectelectro-inagnet does not have all of its winding within the control ofboth of the subscribers. The core of the electro-magnet 70 has anarmature 0 that may be provided with an armature lever p for normallyupholding a shutter g but adapted to release said shutter when eithercoil of the electromagnet is energized, whereby either subscriber mayefiiect a set clearing-out signal. After a subscriber has operated hisgenerator 0, assuming the cord circuit to be connected with saidsubscribers line, the shutter 9 in any event is released, therebyconveying to the operator a signal that ordinarily would be interpretedin the operation of magneto switch-boards, as a clearing-out signal. Bymeans of my invention if the signaling subscriber did not intend toconvey a disconnect signal, or while intending to convey such signal sofar as his connection with another subscriber was concerned, desiredalso the attention of the operator, such subscriber would continue theoperation of his generator, thereby causing the armature 0 of the magnet70 to vibrate, whereby the operation of the supplemental signal device1" would be effected, this sup- .gplemental signal device being providedto perform the function that the signal device 9 is not capable ofperforming, namely, of conveying to the operator the intelligence that asubscriber desires her attention. This signal device is desirably in theform of a small incandescent lamp included in normally open circuit witha battery 8, the circuit for said battery and lamp including terminalsthat are controlled by the armature 0 and are normally separatedthereby, these terminals being brought together each time the armatureis attracted through the influence of the wave form current impressedupon one or the other of the coils Z and m; thus the supplemental signaldevice 1' is performing its function only when a generator 0 is inoperation. I have shown in association with the telephone line extending to the subscribers station a, a line electro-magnet 70 adaptedto be operated by the generator before the cord circuit is connectedwith the line. This magnet 71 is in many respects similar to the magnetZ; in its associations, the magnet 70 having elements 0 p and 9 that aresimilar to the elements 0 p Q previously described, the function of theelement 9 however, being to indicate to the operator that a connectionis desired. The line magnet is also associated with a supplementalsignal 9- included in circuit with a battery 8, the circuit includingthe elements r and 8 being normally open at the armature of the'magnet bbut being closed upon each energization of the magnet 70 due to theintermittent impulses of current impressed upon the magnet 70 by thecalling generator 0. If the operator fails to respond to the line signaloccasioned by the falling shutter 9 the calling subscriber, bymanipulating his generator 0, will cause the signal device 71 tooperate, thereby again to invite the operators attention to the factthat he desires a connection, the line signal device g being incapableof performing this latter function. I have not indicated the line signalapparatus 70 in association with any other of the lines illustrated, asthis would not be, necessary to an understanding of my invention.

The apparatus illustrated in F i 2 is in the main similar to theapparatus illustrated in Fig. 1, and similar parts are given similarcharacters of reference. The coils Z and m in Fig. 2 are provided uponindependent cores and two of the terminals are separated by a condenser71, while the remaining two terminals of these coils, instead of beingdirectly united as is the case in Fig. 1, are separated by a condenser15, of small capacity for reasons well known, these condensers a and I?being preferably of small capacity for the same reasons as outlinedabove in connection with condenser 12. of Fig. 1. The electro-magnetincluding the coil Z, has control of a clearing-out signal device a andJ supplemental signal device 1; that have association with saidelectro-magnet similar to the association of the elements 9 and a" withthe electro-magnet 70, though in the system of Fig. 2, as has beenintimated, the signal devices a and o are alone operated by the callingsubscriber. -The electro-magnet including the coil 172- has associatedtherewith signal devices w and 0: that are similar in ofiice andassociation to the signal devices u and 'v, with the exception thatthese devices w and 92 are alone within the control of the calledsubscriber.

While I have herein shown and particularly described the preferredembodiment of my invention, I do not wish to be limited to the precisearrangement shown, as changes may readily be made without departing fromthe spirit of my invention, but,

Having thus described my invention, I claim as new and desire to secureby Letters Patent the followingz 1. A telephone exchange systemincluding subscribers lines extending from sub-stations toan exchange,cord circuits at the exchange for connecting subscribers inconversation, manually operated means at the sub-stations for impressingwave form current upon the telephone lines, two supervisory clearing-outapparatuses, one limited to operative association with one end of thecord circuit and the other limited to opera tive association with theother end of the cord circuit, whereby one apparatus is within thecontrol of the calling subscriber and the other is within the control ofthe called subscriber, each of said apparatuses including anelectro-magnet adapted to be energized by said wave form current, asignal element adapted for operation by said electro-magnet and, whenoperated, to assume a set display condition, a supplemental signaldevice, and a circuit therefor, said supplemental signal device beingnormally excluded from its circuit by said electro-magnet and beingincluded in said circuit by said elect-ro-magnet when energized.

2. A telephone exchange system including subscribers lines extendingfrom sub-stations to an exchange, cord circuits at the exchange forconnecting subscribers in conversation, manually operated means at thesubstations for impressing wave form current upon the telephone lines,two supervisory clearing-out apparatuses, one limited to operativeassociation with one end of the cord circuit and the other limited tooperative association with the other end of the cord circuit, wherebyone apparatus is within the control of the calling subscriber and theother is within the control of the called subscriber, each of saidapparatuses including an electro-magnet adapted to be energized by saidwave form current, a signal element adapted for operation by saidelectro-magnet and, when operated, to assume a set display condition,and a supplemental signal element normally inert but brought into actionby the electro-magnet when energized.

8. A telephone exchange system including subscribers lines extendingfrom substations to an exchange, cord circuits at the exchange forconnecting subscribers in conversation, manually operated means at thesub-stations for impressing wave form current upon the telephone lines,clearing-out signal apparatus in association with said cord circuitsincluding an electro-magnet adapted to be energized by said wave formcurrent, a signal element adapted for opera tion by said electro-magnetand, when operated, to assume a set display condition, a supplementalsignal device, and a circuit therefor, said supplemental signal devicebeing inert when the electromagnet is de energized but brought into andmaintained in action by the electromagnet only when energized.

4. A telephone exchange system including subscribers lines extendingfrom sub-stations to an exchange, cord circuits at the ex change forconnecting subscribers in conversation, manually operated means at thesub-stations for impressing wave form cur rent upon the telephone lines,clearing-out signal apparatus in association with said cord circuitsincluding an electro-magnet adapted to be energized by said wave formcurrent, a signal element adapted for operation by said electro-magnetand, when operated, to assume a set display condition, and asupplemental signal element being inert when the electromagnet isdeenergized but brought into and maintained in action by theelectro-magnet only when energized.

5. A telephone exchange system including a subscribers line extendingfrom sub-stations to an exchange, means at the exchange for connectingsubscribers in conversation, manually operated means at the sub-stationsfor impressing wave form current upon the telephone lines, a signal.apparatus at the exchange including an electro-magnet adapted to beenergized by said wave form current, a signal element adapted foroperation by said electro-magnet and, when operated, to assume a setdisplay condition, a supplemental signal device, and a circuit therefor,said supplemental signal device being inert when the electromagnet isdenergized but brought into and maintained in action by theelectromagnet only when energized.

6. A telephone exchange system including a subscribers line extendingfrom sub-stations to an exchange, means at the exchange for connectingsubscribers in conversation, manually operated means at the sub-stations'rought into and maintained in action by 10 the electro-magnet only Whenenergized.

In Witness whereof I hereunto subscribe my name this first day of AprilA. D., 1908.

VILLIAM A. FRIGKE.

ated, to assume a set display condition, and Witnesses: a supplementalslgnal element being inert G. L. CRAGG, when the electromagnet 1sdenerglzed but L. G. STROI-I.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

